Be forewarned, this thread has a lot of large images and may take a while to load on a dial-up internet connection.

In this tutorial, you'll see how to model a Gillig Phantom school bus in Google SketchUp. The techniques here can be applied to model any school bus, as the Gillig Phantom shares a lot of similar attributes to modern school buses built today.

To begin, you'll need to set the template to U.S. Feet and Inches.

The rest, is as follows: (Captions to each step are below each image corresponding to that step)

Using the "Tape Measurer" tool, we'll begin by setting guides out along each of the horizontal axes and the vertical axis. In this case, we want to begin with the green axis, and from the intersecting lines that form the X, Y, and Z axes, we'll measure out on the Green axis out to a length of 40 feet. A few inches plus or minus is acceptable. In this screenshot, the guide lines that follow show up as dashed lines with the marker set as a crosshair.

We then repeat this step, again beginning out from the X,Y,Z intersection, and then measure out a distance of 8 feet. This sets the boundary for what will become the "footprint" of the bus.

Then, we grab the "Rectangle" tool, and draw out a rectangle from the 8-foot mark, and then join the other corner at the 40-foot mark. If this works correctly, as above, you'll see your rectangle automatically become a flat plane, for which we then use the "Push-Pull" tool which is located right next to the paint bucket's button in the tool bar above. We want to create a brick that roughly looks like the one above.

Then, using the Tape Measure" tool, we want to create a marker from the bottom up on the "Blue" axis to a height of 11 feet (the average height of a school bus). Then, using the Push-Pull tool, push or pull the top of the brick down to the eleven foot height.

Next, repeat the process from below, lifting the bottom of the brick (which will become the school bus in about an hour or two) up about two feet. Use the tape measure to check your measurements as you go.

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Next, we begin by softening the corners. Since school buses never have a "straight right angle" to any surface, we have to add a little softening to the edges. We begin by selecting the "Arc" tool, and then very close to the outside corners, we start by drawing a line at a 45-degree angle. If done right, your line will "turn pink" to let you know you've reached tour proper angle...

...and then begin moving your arc until it again turns pink. This will let you know you've reached the proper tangent to create a seamless arc that will give you less hassle later on. Repeat this process for all 4 corners, and then...

...again using the Push/Pull tool, we'll create the rounded corners by starting from the top and pushing the outside portion of the corner down to where it "snaps" with the bottom. At that point, the corner is formed and any excess material is automatically discarded.

Now, it starts to get a little complicated. Remember that 11-foot marker? Keep it, but we need to drop the height of our "brick" down to around 4 feet six inches off the ground. This sets our "floor" height within the model. From here, we'll build the sides, front, rear, and then the roof, as separate steps.

This step requires a little trial and error, but to begin we draw a line parallel to the rear of the bus three feet forward. This line becomes the separator that will later form the back "luggage shelf" and back seat. Lift, using the Push/Pull tool, everything rear of this line up a distance of a couple feet or until it closely resembles what's seen here. Repeat the process up front, to again resemble what is seen here. As explained above, this step requires a lot of trial and error, and is one of the most intensive steps in creating your model.

This step here illustrates the process of creating the rear body wall and rear exit window panel for the Gillig Phantom school bus. What I've done here is, via using the Push/Pull tool (along with holding down the "Ctrl" key) is to create a third component to the rear end by extruding the rear seat area yet still keeping our back seat area intact. (You may or may not have to delete a few panels, but this is also a trial and error step). Once extruded (you want to keep the front and rear portions at least a couple feet below the final build height, to allow for the roof later), I selected the top surface of the extrusion and using the "Move" tool, I moved it forward several inches to give the back end that typical look of a modern school bus.

After drawing a few lines, and further extrusion, this is what you should end up with in the next step.

Using the Line and Arc tools, we then refine what will become the inside of the back of the bus. using the images above, we see how I laid out a straight line, and then two arcs, to give the body some depth. You'll also see I deleted some elements, and then recreated them by hand using the line tool.

With the rear exit window created. This is an extrude process involving the rectangle tool. Up front, you'll need to create your stepwell. Begin by drawing a rectangle the total size of your stepwell, but using the Push/Pull tool, push the floor down to only within a couple inches of the bottom of your model. If you go all the way down, you may find yourself creating a huge hole, and we don't want that! LOL. The rest of the stepwell is created by individually creating each step as a "rectangle" by starting on the bottom step. Create your rectangle, extrude to the desired height for the first step, and then repeat the process for the next step.

Next, we start building the sides of the bus. Begin by drawing out a line parallel to the outside edge along the entire length of the bus. Do the same for the other side, and then using the Push/Pull tool, extrude roughly two and a half feet from the floor. This creates the window sill line. An easy method of making sure your measurements are the same on the other side, is when extruding, drag the cursor to the top of the previously extruded rail. This ensures consistency in your model.

You may notice that here, I've left the window opening for the driver open, and the door entry. This we''ll model later.

Before proceeding to the next step, press the CTRL key while using the Push/Pull tool, and extrude the sidewall of the bus up once more to the height of the top of the bus as you currently have it within your model, which should look like...

...this. Here, it's also now OK to start applying some basic color to the model. SketchUp has some excellent color choices, but to match School Bus Yellow, select the color "Color_D02". To add texture to the inside, I used the "Metal: Rough" texture to simulate the stainless interiors of the Gillig Phantom.

Next, we begin to "cap" off the model by applying the roof. We begin by drawing a rectangle on top of the outside edges of the bus, and then once more, extruding back up to that final 11-foot mark we created earlier. To hollow it out, create a series of arcs that will form both the outside and inside of the roof. This process is tedious and once again requires a lot of trial and error (total amount of arcs needed should not exceed six; three per side. A main one for the main portion, and two smaller ones that make up the outside egdes). Once completed, using the Push/Pull tool, hollow out and finish off the roof. Apply texturing, and then proceed to the next step.

Here, using the "CTRL+ Push/Pull tool extrude method, I've created the front roofcap, and then refined it. I'm a detail-freak, so I created as accurate a roofline to the original Phantom seen here by rejoining the modified curve here with line segments that meet at the endpoints of the main curve. This seals up any open spots and creates a seamless look.

After closing up any holes, I like to smooth out any blocky looking curves with the "Soften Edges" dialog. Select the surface to smooth out, and then select Edit--> Surface ---> Smooth Edges. I prefer the settings to be around 29 degrees, as it creates a nice smooth surface without creating any polygon display abnormalities.

Next, draw a rectangle on the side to draw one side window. This step requires a certain degree of trial and error, but using that one rectangle, we then, by using a copy-and-paste method, paste copies of the rectangle down the side. Be sure each rectangle shares the same top and bottom line!

Using the Push/Pull tool, we then hollow out each window opening by snapping the outside surface to the inside, which automatically creates an opening. To create a more advanced window, redraw a rectangle along the outside egdes of the original opening, and then apply a translucent texture to it (you'll need to do this to both sides! You can see here that using techniques to build a majority of the 3D model will be repeated on most every feature of your model.

If you'd like to take a look at mine and view my models within SketchUp, click this link: